Iontophoresis is a method for introducing ionic substances into body tissues which has proven to be very useful in numerous medical applications. The method most often utilizes direct electrical current to drive ionized substances such as chemicals or drugs placed on the skin through the intact skin or other body surface to the interior of the body. Iontophoretic systems generally comprise an iontophoretic current generator and a pair of electrodes with the ionic substance to be introduced into the body tissue contained between the appropriate polarity electrode and the body. The current generator may take any number of different forms but generally is a hand-held or table-supported instrument which is connected to the electrodes by means of leads. Because the ionic substances generally available for use with iontophoretic systems are fluid solutions or gels, electrode systems must provide seals and means for holding the electrodes securely in place. Therefore, their placement to and transfer from or on the patient's body is a task requiring relatively high skill levels.
Like iontophoresis, electrical tissue stimulation, also known as nerve stimulation, has also been proven to be useful and effective in many medical applications. One of the most common usages of electrical tissue stimulation is for the relief of chronic and acute pain. For such stimulation, both DC and AC (biphasic) currents can be used. However, biphasic stimulation is considered by those knowledgeable in the art as safer and more effective. Other applications for electrical tissue stimulation include muscle exercising, bladder stimulation and bone stimulation.
Electrical tissue stimulation may be delivered to the affected tissue transcutaneously, or it may be applied directly to subcutaneous tissue through implanted electrodes. Transcutaneous stimulators are generally carried or worn by the patient and are connected through leads to electrodes secured to the patient's body. Implantable or subcutaneous stimulators usually comprise implantable electrodes having a receiver connected thereto and a stimulation transmitter which transmits electromagnetic stimulation energy through the skin to the receiver where the energy is demodulated and delivered to the implanted electrodes. Other subcutaneous nerve stimulators provide for the implantation of the entire device, with control provided by an electromagnetic link.
Conventionally, iontophoretic and biphasic stimulation devices are used independently of each other, i.e. the corresponding stimulation methods have not been routinely or systematically integrated in treatment regimen. However, medical research indicates significant benefits where the two methods are cooperatively combined. One promising area for the integrated use of iontophoretic and biphasic tissue stimulation is for the relief or control of pain. For one example of the integration of these methods for control of pain in the field of physical therapy see Joseph Kahn, MS, PT, Electrotherapeutic Approach to Postoperative Pain Following Total Hip Replacement: A Case Study, The Journal of Orthopedic and Sports Physical Therapy, Spring, 1981. There are many other possible applications for the combined or integrated use of iontophoresis and electrical tissue stimulation. One possible use is the area of sports medicine, where the integration of electrical tissue stimulation and iontophoresis could be particularly useful in dealing with joint pain and muscle rehabilitation.
Heretofore, there has not been provided a device integrating iontophoresis, electrical tissue stimulation and operating mode timing control capability in a single common-lead-and-electrode device. Therefore, in the case where the needs of the patient require or suggest iontophoretic treatment periodically interchanged with electrical tissue stimulation, the iontophoretic device must be exchanged with a tissue stimulation device, normally requiring the exchange of electrodes also. Obviously, due to the precision and care with which the iontophoresis electrodes must be attached and reattached, and the need for initial adjustments of each device, the procedure is time consuming and relatively difficult. Also, the procedure forecloses the relatively rapid alternation or interchange between the two stimuli. Furthermore, stimulus mode timing (i.e. timing of mode repetition period and duration) is complicated by the necessity of user or staff intervention.